Method for preparing dust control fabrics

ABSTRACT

EMULSIFIABLE FLAME RETARDING COMPOSITIONS FOR PREPARING DUST CONTROL FABRICS ARE DISCLOSED. THE COMPOSITIONS COMPRISE AN OIL HAVING A FLASH POINT ABOVE ABOUT 150*C., A FLAME RETARDING ORGANIC PHOSPHATE ESTER AND EMULSIFYING AGENT. THE THESE COMPOSITONS READILY FORM AQUEOUS EMULSIONS FRM WHICH THE OIL COMPOSITION IS EXHAUSTED ONTO DUST CONTROL FABRICS SUCH AS CLOTHS AND MOPS. SUCH TREATED DUST CONTROL FABRICS EXHIBIT IMPROVED FLAME RETARDENCY AND DUST COLLECTING PROPERTIES.

United States Patent US. Cl. 117136 5 Claims ABSTRACT OF THE DISCLOSURE Emulsifiable flame retarding compositions for preparing dust control fabrics are disclosed. The compositions comprise an oil having a flash point above about 150 C., aflame retarding organic phosphate ester and emulsifying agent. These compositions readily form aqueous emulsions from which the oil composition is exhausted onto dust control fabrics such as cloths and mops. Such treated dust control fabrics exhibit improved flame retardancy and dust collecting properties.

This is a division of application Ser. No. 6,972, filed Jan. 29, 1970, now US. Pat. No. 3,695,926.

BACKGROUND OF THE INVENTION This invention relates to emulsifiable flame retarding compositions, to processes for a applying said compositions to dust control fabrics, and to the fabrics so prepared.

Oil-treated or impregnated fabrics have been used extensively to remove dust, dirt, and other powdery deposits from furniture, floors and walls. Such oily fabrics are utilized because of the dust-attracting properties of the oil which also serves to retain the dust until the fabric is washed. One of the problems with such oiltreated or impregnated fabrics results from the flammability characteristics of the oil itself. Oil-treated mops and dusting cloths present a fire hazard during storage or in use, especially when it is possible for these fabrics to come in contact with warm or burning objects such as cigarettes, or as a result of heat generated through friction and static electricity. Such treated fabrics also are capable of ignition through spontaneous combustion on storage in areas where high temperatures are possible.

SUMMARY OF THE INVENTION These other problems associated with dust control fabrics have been overcome by treating the dust control fabrics with an emulsifiable flame retarding composition comprising from about 1 to 50 parts of an oil having a flash point of above about 150 C., from about 20 to 80 parts of a flame retarding organic phosphate ester and up to about 20 parts of an emulsifying agent. These compositions may be applied to the fabrics in any conventional manner such as by spraying from an organic solvent or preferably by exhausting the composition into the fabrics from an aqueous emulsion. The dust control fabrics prepared in this manner exhibit improved flame retardancy without loss of the desirable attraction for dust particles. Particularly improved flame retardant and dust attracting properties are obtained when synthetic aliphatic polyester oils are utilized in the composition.

3,814,624 Patented June 4, 1974 DESCRIPTION OF THE PREFERRED EMBODIMENTS This invention involves compositions comprising an oil, an organic phosphate ester and an emulsifying agent. This oil composition is readily emulsified in water by stirring. When dust control fabrics are contacted with the aqueous emulsion, the oil and organic phosphate ester are exhausted on the fabric from the emulsion.

The oils which are useful in the formulation of the flame retardant compositions of the invention are those having a flash point above about 150 C. The oils may be the readily available mineral oils, although oils of animal, vegetable or synthetc origin are useful. Examples of synthetic oils which may be used are polyesters and polymerized olefins such as polyisobutene, polypropylene, polymerized cracked paraifin waxes, etc. Although the mineral oils are used more often due to the commercial and economical feasibility, the synthetic polyester oils and particularly the synthetic aliphatic polyester oils are preferred since these provide the maximum flame retarding properties to the composition. Examples of such synthetic aliphatic oils include dioctyl adipate, dioctyl sebacate, dioctyl or didodecyl adipate and di-Z-ethyl hexyl sebacate polymers obtained from the dibasic acid and the corresponding alcohols or glycols. Epoxidized soyabean oil is another example of a synthetic oil. Examples of synthetic aromatic esters are those low molecular weight polymers obtained from aromatic dibasic acids such as phthalic acid with alcohols and glycols such as butyl alcohol, hexyl alcohol and ethylene glycol.

Mineral oils useful in the preparation of the composition of the invention may be hydrocarbon oils having a. viscosity value of from 50 SUS (Saybolt Universal Seconds) at F. to 200 SUS at 210 F. Mixtures of the oils of different sources likewise are useful. Such mixtures are available from mineral oils (paraffinic or naphthenic), vegetable oils, animal oils, synthetic oils of the silicon type, synthetic oils of the polyolefin type, synthetic oils of the polyester type, etc.

The organic phosphate esters useful in this invention are the tri-esters of phosphorus or phosphoric acid in which the ester radical is derived from a substantially bydrocarbon radical including the aryl, alkyl, alkaryl, arylalkyl, or cycloalkyl radical as well as hydrocarbon radicals having polar substituents such as chloro, bromo, nitro, fluoro etc. Particularly desirable phosphates are those in which the ester radicals are phenyl, alkyl phenyl or alkyl radicals containing from 3 to 8 carbon atoms. Examples of such phosphates include triphenyl phosphate, tricresyl phosphate, cresyl diphenyl phosphate, tris- (1,3-dichloropropyl) phosphate, tris(2,3-dichloropropyl) phosphate and tris (1-bromo-3-chloro isopropyl) phos phate. These latter phosphate esters containing halogen appear to be most effective in improving the flame retardant properties of the composition, but the nonhalogenated phosphate esters provide adequate flame retardant protection at much lower cost.

In addition to the oil and the phosphate ester, the compositions of the invention may contain up to about 20 parts of an emulsifying agent. Although the various types of emulsifying agents, namely, cationic, anionic and non ionic agents are effective to varying degrees, the cationic agents are particularly preferred for emulsifying the compositions of this invention. The principal cationic agents are the quaternary amine salts wherein at least one of the substituents on the nitrogen is a long-chain alkyl group and the anion is either chloride or bromide. Examples of such cationic emulsifying agents include distearyl dimethyl ammonium chloride, dicoco dimethyl ammonium chloride and di-soya dimethyl ammonium chloride as well as the various n-alkyl trimethyl ammonium chlorides commercially available under the trade designation Arquad from Armour Industrial Chemical Company; and polyethoxylated quaternary ammonium chlorides, also available from Armour under the trade designation Ethoquad.

Other well known emulsifying agents such as the nonionic emulsifying agents may be utilized although the above described cationic emulsifying agents are preferred. Thus the emulsifying agent may be a mono-aryl ether of an aliphatic glycol. Specific examples include mono phenyl ether of ethylene glycol, mono-(heptylphenyl) ether of triethylene glycol, mono-(alpha-octyl-betanaphthyl) ether of tetrapropylene glycol, mono-(polyisobutene (molecular weight of 1000)-substituted phenyl) ether of octapropylene glycol, and mono-(o,p-dibutyl-phenyl) ether of polybutylene glycol, mono-(heptylphenyl) ether of trimethylene glycol and mono-(3,5-dioctylphenyl) ether of tetratrimethylene glycol, etc. The aliphatic glycol may be a polyalkylene glycol. It is preferably one in which the alkylene radical is a lower alkylene radical having from 1 to carbon atoms. Thus, the aliphatic glycol is illustrated by ethylene glycol, trimethylene glycol, propylene glycol, 1,2-butylene glycol, 2,3-butylene glycol, tetramethylene glycol, hexamethylene glycol, or the like. These mono-aryl ethers are obtained by the condensation of a phenolic compound such as an alkylated phenol or naphthyl with one or more moles of an epoxide such as ethylene oxide, propylene oxide, trimethylene oxide, or 2,3-hexalene oxide. The condensation is promoted by a basic catalyst such as an alkali or alkaline earth metal hydroxide, alcoholate, or phenate. The temperature at which the condensation is carried out may be varied within wide ranges such as from room temperature to about 250 C. Ordinarily it is preferably 50l50 C. More than one mole of the epoxide may condense with the phenolic compound so that the product may contain in its molecular structure one or more of the radicals derived from the epoxide. A polar-substituted alkylene oxide such as epichlorohydrin or epibromohydrin likewise is useful to prepare the mono-aryl ether product and such product likewise is useful as the emulsion stabilizer in this invention.

Likewise useful as the emulsifying agents are the monoalkyl ethers of the aliphatic glycols in which the alkyl radical is, e.g., octyl, nonyl, dodecyl, behenyl, etc. The fatty acid esters of the mouo-aryl or mono-alkyl ethers of aliphatic glycols also are useful. The fatty acids include e.g., acetic acid, formic acid, butanoic acid, hexanoic acid, oleic acid, stearic acid, behenic acid, decanoic acid, isostearic acid, linolenic acid, as well as commercial acid mixtures such as are obtained by the hydrolysis of tall oils, sperm oils, etc. Specific examples are the oleate of mono- (heptylphenyl) ether of tetraethylene glycol and acetate of mono-(polypropene (having molecular weight of 1000) -substituted phenyl)ether of tri-propylene glycol.

The alkali metal and ammonium salts of sulfonic acids likewise are emulsifying agents. The acids are illustrated by decylbenzene sulfonic acid, di-dodecylbenzene sulfonic acid, mahogany sulfonic acid, heptylbenzene sulfonic acid, polyisobutene sulfonic acid (molecular weight 750), and decylnaphthalene sulfonic acid, and tri-decylbenzene sulfonic acid. The salts are illustrated by the sodium, potassium, or ammonium salts of the above acids.

In addition to the oil, phosphate ester and emulsifying agent, the composition of this invention also may contain varying amounts of supplementary additives such as plasticizers, germicides, perfumes, coloring matter, etc. Known plasticizing compositions such as dioctyl phthalate have been incorporated into the c mp itions in amounts up to about 15 parts. Smaller amounts of germicides may be incorporated, and examples of these include various quaternary ammonium salts such as those described above as being useful as emulsifiers and phenolic compounds such as orthophenyl phenol.

As mentioned previously, the compositions of this invention wherein the oil is a synthetic aliphatic polyester oil, are preferred over compositions containing mineral oil because of the improved flame retardant properties imparted to the dust control fabric when larger amounts of the composition are utilized. For example, when larger amounts of mineral oil containing compositions are applied to the fabrics to improve the dust pickup, the flame retardant properties decrease. On the other hand, when similar amounts of the composition of this invention containing the synthetic aliphatic polyester oils are applied to the same fabrics, the dust attracting and flame retardant properties of the treated fabric are improved dramatically.

The fabrics which may be treated in accordance with the process of this invention include those fabrics customarily used for dust control fabrics. These include fabrics comprised of cellulosic, keratinic and synthetic fibers. Fabrics prepared from cellulosic fibers are most often used in the dust control industry and such fibers include cotton, cellulose acetate and regenerated cellulose such as viscose rayon. Suitable synthetic fibers which may be utilized either alone or in combination with the cellulosic fibers in the preparation of suitable substrate fabrics include synthetic polymeric fibers such as polyamides (e.g., polyhexamethylene adipamide), acrylates, (e.g., polyacrylonitrile) and polyesters such as the various types of polyethylene terephthalate. Specially prepared flame retardant fibers also may be utilized in prepared fabrics. An example of such fiber is known as PFR Rayon available from American Viscose. Cotton mops treated with commercially available flame retardant chemicals such as tetrakis-hydroxy methyl phosphonium hydroxide available from the Hooker Chemical Company or Pyrovatex CP (a reactive phosphorus compound available from Ciba) also constitute pre-treated fabric substrates which can be improved by this invention. Another Well known treatment for improving the flame retarding properties of the substrate fabric is a treatment with a combination of borax and boric acid in ratios of about 2.5 to 1. About from 4 to 10% of the boraxzboric acid mixture is applied to the fabric, based on the weight of the fabric to provide the desired flame retardant properties. However, the fabrics treated with these compositions do not possess sufficient dust pickup properties to be acceptable for these applications. When the dust pickup characteristics of the fabrics are improved by applying a dust-attracting oil to the fabrics, the improvement imparted by the flame retardant is diminished by the presence of the flammable oils. This deficiency is overcome by the composition of the present invention. When the compositions of the invention are applied to fabrics which have been treated with the chemicals described above such as the boraxzboric acid composition, dramatically improved flame retardant and dust pickup properties are imparted to the fabric, and the amount of the composition applied to the fabric can be reduced to levels of about 5 to 15% based on the weight of the fabric.

The fabrics to be treated with the compositions of the inventions may be woven, knitted, nonwoven, or stranded fabrics. In general, the composition of this invention may be applied to any fabric to improve its dust-attracting properties and its flame retardant characteristics. Such fabrics would include those used in the preparation of mops, dust cloths, dust tool covers, etc.

As mentioned previously, the compositions of this invention may be applied to the fabric neat, in solution or as an emulsion. Emulsions or solvents are preferred because of the ease of application. Aqueous emulsions may be prepared easily by adding the compositions of the invention to water with stirring. The amount of water is Composition A:

not critical although the time required for exhausting the composition into the substrate is proportional to the concentration of the composition in the water. When exhausting this composition into the substrate, the substrate is merely placed into the emulsion and usually agitated until the desired amount of the composition is exhausted onto the fabric or until all of the composition is exhausted onto the fabric as is evidenced by the formation of a clear water phase. The treated fabric then is removed from the water and dried. The rate of exhaustion also is proportional to the temperature of the emulsion. At higher temperatures, the exhaustion is more rapid. The process is complete at room temperature in about three to six min utes. The rate of exhaustion from an emulsion is increased dramatically by the addition of a dcmulsifier such as tetrasodium pyrophosphate during the exhaustion.

The following examples illustrate the compositions and the processes of this invention. Unless otherwise indicated, all parts and percentages are by weight.

Parts Mineral oil having a flash point of about 213 C. and a viscosity of from 54-74 cps. at

38 C. 10 Tris-dichloropropyl phosphate 80 Di-soya dimethyl ammonium chloride 10 Composition B:

Mineral oil as in Composition A 5 Tricresyl phosphate 75 Di-stearyl dimethyl ammonium chloride 15 Composition C:

Paraplex G-54 (a synthetic aliphatic polyester oil commercially available from Rohm and Haas Company) 8 Cresyl diphenyl phosphate 80 Di-coco dimethyl ammonium chloride (available as Arquad 20-75 from Armour Chemical Co.) 10 Composition D:

Paraplex G-54 6.5 Houghto-Sa-fe 1120 (an aryl phosphate ester available from E. S. Houghton and Co.) 66.6 2-ethylhexyl diphenyl phosphate 13.4 The ammonium chloride of Composition C 2.0 Emulsifier M85 (a cationic emulsifying agent available from Northern Textile Chemical Company) 5.4 Composition E:

Paraplex G-20 (a sebacic acid-type polyester available from Rohm and Haas Company) l Tris (1-bromo-3-chloro isopropyl) phosphate 75 Arquad 20-75 Ortho phenyl phenol 1.5 Composition F:

Houghto-Safe 1120 40 Emulsifier M85 3 Arquad 2C-75 1 Paraplex G-54 4 Cosmoline (Mineral oil with acid neutralizer available from E. S. Houghton & Co. under the designation \RV) 0.5

Composition G:

Same as Composition F except that 21 parts of 'Paraplex G-54 is used in the composiiton. Composition H:

Similar to Composition F except that the Paraplex G-54 is replaced by an equivalent amount of dioctyl phthalate.

Composition I:

Similar to Composition F except that the Paraplex G-54 is replaced 'by an equivalent amount of mineral oil.

The improved flame retardant properties of the dust control fabrics treated with the compositions of this invention are shown by treating one pound cotton stranded mops with emulsions of the compositions containing varying amounts of oil and thereafter measuring the flame retarding characteristics of the mops at different angles.

Several one pound cotton mops were placed in pails containing the compositions identified as Compositions F through I diluted with water to an approximate volume of two liters per mop. The mops were agitated for a period of about 3 to 6 minutes in the emulsion at room temperature until the water became clear. The mops were removed from the pails, centrifugally spin dried and then tumble dried at an elevated temperature. The dried mops were then conditioned overnight in a controlled atmosphere of a temperature of 70 F. and a relative humidity of 65% prior to being subjected to the following flammability tests.

In this flammability test, the mop fabrics are main tained in a certain position and one end of the mop is ignited for 5 seconds whereupon the source of the flame is removed. The time, distance of burning and any afterglow is observed and recorded. Based on these observations, the flame retardant characteristics of the mops are indicated by rating the mop on a scale of from 0 to 10, 0 indicating no flame retarding characteristics (complete burn) and 10 indicating no burn. The results of this test on mops maintained in four dilferent positions, namely, horizontal, a 45 angle, a 75 angle and in the vertical position, are summarized in the following table. The data indicates a dramatic and significant improvement in the flame retardant properties of the treated mop fabrics. The dust-attracting properties of these mops are excellent.

Treatment level,

percent Ratings 75 angle Horizontal 45 angle Mop Composisample tion 1 Control 0 Mineral oil.-

Vertical Total I Burns faster than untreated control.

It has been observed that the compositions of this invention wherein the oil is a synthetic linear polyester oil may be applied to fabrics at high levels of add-on to increase the dust pickup properties without drastic atfect on the flame retardant properties of the fabrics. On the other hand, when mineral oils or synthetic aromatic polyester oils are used in the compositions, increased pickup results in a decrease in the flame retardant characteristics. For example, when Compositions F, H and I are exhausted on cotton mops as described above but to an addon level of 30%, the rating totals for the flammability test are 37, 14 and 18, respectively. These data demonstrate the clear superiority of the synthetic aliphatic polyester oils in the compositions of the invention.

That which is claimed is:

1. A process for preparing flame retardant dust control fabrics comprising preparing a self-exhausting aqueous emulsion of an oil composition consisting essentially of a liquid polyester oil having a flashpoint above about 150 C., a flame retarding organic phosphate ester, and an emulsifying agent, contacting a fabric with the emulsion until the water becomes clear and drying the treated fabric.

2. A process as defined in claim 1 wherein the oil composition contains from about 1 to 50 parts of the polyester oil, about 20 to parts of the organic phosphate ester, and up to about 20 parts of the emulsifying agent.

3. The process of claim 1 wherein the oil is a synthetic aliphatic polyester oil.

4. The process of claim 1 wherein the phosphate ester is a haloalkyl phosphate ester containing from about '3 to 8 carbon atoms in the alkyl radical.

5. The process of claim 1 wherein the composition 1,258,637 3/191 8 Smelling 15104.93

also contains up to about 15 parts of a plasticizer. 2,957,785 10/1960 Leatherland 117-1385 3,038,820 6/1962 Albrecht 117-1395 CQ References Cited 2,536,978 1/1951 Fordemwalt 117-136 UX GWINNELL, Assistant Examiner 2,751,039 6/1956 Hanly 55524 2,347,031 4/1944 Cupery 55- 524 2,122,514 7/1938 Crocker et a1. 55524 117--113, 138.8 B, 143 R, 144; 2528.1

1,344,545 6/1920 McGregory 15 104.93

UNI ED sTATEs PATENT OFFICE CERTIFICATE OF CORRECTION Patent b, 3; 814, 624. Dated June 4, 1974 lnventgrks) Alexander A- Scarborough It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 5', Composition D. and Composition F., E. S. Houghton and Co."'shou1 d reed --E. F. Houghton and Co.

Column 5, Composition D, Northern Textile Chemical Company should read --Northern Petrochemical Company".

C Signed and sealed this 1st day of October 1974.

(SEAL) Attest:

McCOY M. GIBSON JR. c. MARSHALL DANN Attesting Officer 7 Commissioner of Patents USCOMM-DC 60376-P69 4' u.s. GOVERNMENT PRINTING ornc: Iss9 o-ass-au.

F ORM PO-1050 (10-69) UNITED sTATEs PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3, 624'. Dated June 4, 1974 Inv'entor(s) Alexander A. Scarborough It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 5, Composition D. and Composition F., E. S. Houghton and Co. should read --E. F. Houghton and Co.

Column 5, Composition D, Northern Textile Chemical Company" should read --Northern Petrochemical Company--.

Signed and sealed this 1st day of October1974.

(SEAL) Attest: MCCOY M. GIBSON JR. 0. MARSHALL DANN Attesting Officer Commissioner of Patents FORM F'O-105O 0459) USCOMM-DC 60376-P69 w uisv GOVERNMENT PRINTING OFFICE nu 0-366-334. 

